calendar disappeared from phoneSupport

Hi,
my Hero was working perfectly with my googlemail calendar. then today, all the calendar events disappeared from my phone. i have tried unchecking and rechecking my googlemail calendar from the HTC calendar app but to no avail. other calendars work fien with my phone (UK holidays, USA holidays), it's only my googlemail calendar which is linked to my Hero which has stopped working correctly. i have also tried restarting the phone. all the calendar's events are visible online through my computer...they've just suddenly stopped showing up on my phone. any advice/ideas? thanks so much!